Advil is a brand name for ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) that is used to relieve pain and reduce fever [1]. According to Drugs.com, ibuprofen can be taken on an empty stomach, but it may cause stomach upset [2]. It is recommended to take ibuprofen with food or milk to reduce the risk of stomach irritation. GoodRx states that ibuprofen can cause stomach ulcers, bleeding, or perforation, especially in people who are elderly or have a history of stomach problems [3]. It is important to follow the recommended dosage and not to exceed the maximum daily dose of ibuprofen to avoid potential side effects.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.drugs.com/medical-answers/you-ibuprofen-empty-stomach-3572019/
[3] https://www.goodrx.com/acetaminophen/is-tylenol-acetaminophen-bad-for-your-stomach